3rd generation partnership project (3GPP) long term evolution (LTE) is an improved version of a universal mobile telecommunication system (UMTS) and is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) that is an evolution of the 3GPP LTE.
Minimization of driving tests (MDT) is a test performed by operators for coverage optimization by using a user equipment (UE) instead of using an automobile. A coverage varies depending on a location of a base station (BS), deployment of buildings nearby, a user's usage environment, etc. Therefore, it is required for the operators to periodically perform the driving test, and a lot of costs and resources are consumed. The MDT is used when the operator measures the coverage by using the UE.
The MDT can be classified into a logged MDT and an immediate MDT. According to the logged MDT, after performing the MDT measurement, the UE delivers a logged measurement to a network available at a time of a reporting condition. According to the immediate MDT, after performing the MDT measurement, the UE delivers the measurement to the network when a configured reporting condition is satisfied. The logged MDT performs the MDT measurement in a radio resource control (RRC) idle mode, but the immediate MDT performs the MDT measurement in an RRC connected mode.
For the MDT measurement, the UE consumes a battery, and an available memory may decrease. Since the UE further performs an additional operation, a user's prior consent for performing the MDT may be essential.
However, even if the user has a prior consent for the MDT measurement, occasionally, the user may not want to report privacy information of the user to a network. For both of the immediate MDT and the logged MDT, location information of the UE is included in a measurement result. Since this is related to user's privacy, occasionally, it may be necessary for the user not to report location information of the user to the network.
However, there is a need for a method capable of guaranteeing the user's privacy when reporting the measurement result.